"Republicans have enough races within the margin of error to think that even the slightest national breeze blowing in their favor — and that wind looks likely to be there — will be enough to push them over the top," the Post's Chris Cillizza wrote.

Chances of a Republican takeover of the Senate are further bolstered because President Barack Obama "is deeply unpopular," the Post said. Democratic incumbents will not be the standard bearers for their party in West Virginia, South Dakota, and Iowa. In Montana, Sen. John Walsh dropped out in the face of a plagiarism scandal.

GOP incumbents — including Pat Roberts in Kansas and Lamar Alexander in Tennessee — overcame tea party challengers in their primaries, meaning Republican senatorial candidates should have broad appeal in the midterm elections, according to the Post.

Democrats are contesting two Republican-held seats in Georgia and Kentucky. In the latter, Minority Leader Sen. Mitch McConnell is struggling to maintain a narrow lead over Democrat Alison Lundergan Grimes. By nominating David Perdue to run against Michelle Nunn, Georgia Republicans have stayed competitive, the Post said.

It is possible, "but not probable" that Democrats can pull off victories in Arkansas, Alaska, Colorado, Georgia, or Kentucky, the Post reported.

Longtime Democratic consultant James Carville wrote in a commentary for The Hill last week that for the GOP to capture the Senate, as analysts are predicting, it will have to overcome the unpopularity of the Republican Party brand.